This invention relates generally to automatic radio-frequency (RF) real-time high-way toll collection from moving vehicles. It especially adapted to the use of an untraceable electronic check debited from smart card and communicated in a cryptographically sealed envelope message. The invention relates directly to an in-vehicle unit (IVN), noncontact IC card (NIC), a roadside collection station (RCS) and to an overall system incorporating a plurality of RCS""s, IVN""s and NIC""s. The invention may be used for parking collections and other types of road pricing applications.
In addition this invention may be used for individual access control wherein the remote toll systems enable personal authentication and payment.
An automatic toll-paying systems which utilizes a recording medium, for example an integrated circuit card (IC card), of a prepaid system has been previously developed for paying charges for utilization of pay facilities, for example for paying a toll for passage over a toll road or for a passage over a toll-gate in public transport. In such a prepaid systems, a prepaid amount of money is recorded beforehand on a recording medium, and every time a toll road is utilized, a toll for passage is subtracted from the amount of money recorded on a recording medium through wireless communication at a tollbooth gate at an entrance or an exit, and a balance is recorded on the recording medium.
However, in the case of such an automatic toll-paying systems, if a balance recorded on the recording medium is not enough for a necessary amount of money such as a toll for passage it becomes difficult to pay using the recording medium and complicated operations becomes necessary such as a shortage amount must be paid in cash, or this debt has to be stored in the recording medium or in a special accumulator in a vehicle carried device and afterward the debt should be returned to the creditor.
In order to solve the mentioned problems there is a few decisions presently utilized in similar operation comprising communication via electromagnetic waves.
The first group of an automatic toll-paying systems includes a microwave and cryptographic units arranged on-board of a vehicles. This unit comprising reader/writer block to operate with contact computerized and/or memorized prepaid smart cards. U.S. Patents which reflect the discussing area are hereby incorporated herein by reference:
U.S. Pat. No. 5,485,520xe2x80x94Chaum et. al. (1996);
U.S. Pat. No. 5,663,548;xe2x80x94Hayashi et. al. (1997)
U.S. Pat. No. 5,532,689xe2x80x94Bueno et. al. (1996)
U.S. Pat. No. 5,608,417;xe2x80x94de Vall et. al. (1997)
U.S. Pat. No. 5,661,286xe2x80x94Shuno et. al. (1997)
One or more roadside collection stations (RCS) communicate over a short-range, high speed bi-directional microwave communication link with one or more in-vehicle units (IVU) associated with one or more respectively corresponding vehicles in one or more traffic lanes of a highway (U.S. Pat. No. 5,485,520). At least two up-link (IVU to RCS) communication sessions and at least one downlink (RCS to IVU) communication session are transacted in real time during the limited duration of an RCS communication footprint as the vehicle travels along its lane past a highway toll plaza. Especially efficient data formatting and processing is utilized so as to permit, during this brief interval, computation of the requisite toll amount and a fully verified and cryptographically secured (preferably anonymous) debiting of a smart card containing electronic money. Preferably an untraceable electronic check is communicated in a cryptographically sealed envelope with opener. Transaction linkage data is utilized in each phase of the complete toll payment transaction to facilitate simultaneous multi-lane RCS/IVU operation. A plaza computer local area network and downlink plaza controller is also used to facilitate simultaneous multi-lane transactions.
A hand-held portable smart-card reader/writer with radio frequency receiving/transmitting means is disclosed in U.S. Pat. No. 5,532,689 France. Herein is described a method of transmitting data quickly and securely from a smart card during a remote transaction between a fixed station and a mobile item of equipment containing a smart-card reader, said card reader having a fast memory, wherein, on receiving said card, and in addition to storing the data from the card in said fast memory, said reader also stores a pair of data items in said fast memory, one of which data items identifies the number of the card, and the other data item corresponds to an access count indicating the number of accesses to the card, each access by any reader incrementing the access count in the card by unity, and wherein, during the transaction, the mobile item of equipment, which is interrogated remotely by the fixed station, compares said pair of data items stored in said fast memory of said reader with the pair of data items of the card that is currently inserted in the mobile item of equipment, and transmits the result of the comparison and the data of the card, which data is stored in the fast memory, to the fixed station.
However a vehicle carried units for automatic toll payment systems are too complicated device as they operate in a microwave mode similar to cellular telephones and pagers. Furthermore the hand-held and/or vehicle carried unit must have IC card reader/writer with appropriate security functions to prevent tampering and/or using of forged (false) IC cards. All these features add an additional value in the cost of a system, and do not make it versatile and convenience to spread these system to the other market applications. Moreover the vehicle carried units can not be used in individual transport applications like in subway gates or in buses due to it cost, complexity and non convenient to use and wherein person uses individual contactless radio frequency IC cards becoming to be versatile.
The radio frequency (RF) Smart cards become to be a standard convenience element for transport and access applications. These noncontact IC cards and/or tags for performing proximate data communication between IC card and the terminal by using electromagnetic waves and having at least one inductive coil employees antenna for power transfer and data interchange are illustrated in U.S. Patents reflecting these area are hereby incorporated herein by reference:
U.S. Pat. No. 5,444,222xe2x80x94Inoue et. al., 1995;
U.S. Pat. No. 5,394,105xe2x80x94Axer et. al., 1995;
U.S. Pat. No. 5,440,302xe2x80x94Irmer et. al., 1995;
U.S. Pat. No. 5,329,274xe2x80x94Donig et. al., 1994;
U.S. Pat. No. 5,418,358xe2x80x94Bruhnke et. al., 1995;
U.S. Pat. No. 5,449,894xe2x80x94Bruhnke et. al., 1995;
U.S. Pat. No. 5,418,353xe2x80x94Toride et. al., 1995;
U.S. Pat. No. 5,426,667xe2x80x94van Zon et. al., 1995;
U.S. Pat. No. 5,241,298xe2x80x94Lian et. al., 1993;
U.S. Pat. No. 5,317,330xe2x80x94Everet et. al. 1994;
U.S. Pat. No. 5,065,137xe2x80x94Herman et. al. 1991.
Systems for noncontact exchange of data are known in different designs and types. Inductively operating systems comprising radio frequency tags and reader/writer terminal and performing low frequency range less than one megahertz (MHz) that allows to operate at relatively long distances are well known in the art. Such tags provide the advantage of permitting through-the-body operation and easy clock generation. However these low frequency systems can not provide relatively high rate data exchange, an despite that they may operate at relatively long distances the portable carrier must be attendant in a special recognition area during a significant time to provide identification and data transfer. Furthermore these systems can not provide the adequate protection on security level during short interaction time because of low rate of data exchange. Moreover they operate at constant frequency that allow the interception of a signal and hacking of security. In addition the returning signal from tag to the reader is more than 80 dB less than transmitted signal from the reader to the tag.
The embodiment disclosed in U.S. Pat. No. 5,317,330 enables to increase power retransmitted from portable carrier-tag to the reader by means of providing dual resonant antenna which performs parallel resonant at the receive frequency and series resonant at the transmit frequency. The parallel resonant circuit of antenna derives operating power from the signal transmitted by the stationary member. The series resonant circuit transmits the coded information at a second frequency which differs from the first frequency. Two embodiments are disclosed: first where tag transmission is provided with less frequency: divided by two, and second where tag transmission is provided with higher frequency: multiplied by two. However the method of frequency multiplication is not disclosed. Herein the operation is provided at two constant frequencies that allow the interception of a signal and hacking of secure information. The simultaneous operation in the same capture area of a few alike devices is accompanied with signal interference and collisions.
The embodiment disclosed in U.S. Pat. No. 5,608,417 comprising a transponder system employs a transponder antenna with a distributed inductance and capacitance that exhibit parallel and series resonant frequencies. Transmissions to the transponder circuit are made at one or more parallel resonant frequencies to maximize the excitation of the transponder circuit, while return signals transmitted back from the transponder are modulated at one or more series resonant frequencies to maximize the signal current. The transponder antenna is implemented as a pair of aligned coils on opposite sides of a thin dielectric substrate, with the coils connected together through the substrate at one point and the substrate thickness not more than about 25 microns to obtain a significant mutual inductance between the coils. The transponder circuit is designed to respond to the fundamental parallel resonant frequency, at which the maximum voltage is generated by transponder winding, but to transmit the information signal back at a series resonant frequency at which the current in the transponder winding is maximized thus maximizing the strength of the returning signal. The transponder winding has both multiple parallel resonant frequencies and multiple series resonant frequencies. Different parallel resonant frequencies may be used for energizing the transponder at the fundamental and writing to the transponder at the harmonic. Similarly different types of information may be returned from the transponder at a different series resonant frequencies.
However the embodiment of U.S. Pat. No. 5,608,417 suffers of many mutual couplings because of distributed inductive and capacitive parameters, which activate many sub-resonant effects, signal scatters and distorts and therefore electronic circuit for proper signal detection and modulation becomes to be too complicated and expensive. Furthermore this embodiment may operate exclusively with frequencies derived as multiplying from fundamental frequency of parallel resonance. Consequently the simultaneous operation of a more than one transponder with one reader/writer will bring into communication collisions. The data transmission is provided by continuous wave with constant frequency. Security features of transmitted data may be achieved solely with software design and one may intercept and decipher data interchange. In addition the utilization of described embodiment in high-speed access and transit systems, like toll high-way systems and toll gates, is difficult because of collisions occurring while IC cards are using the same frequency assortment at once. Moreover the automatic toll-paying systems utilize special roadside collection stations mounted on a special towers remote from moving vehicles, therefore the demand arises to enlarge the amplitude of electromagnetic energy transmitted to the transponder in order to provide power of on-card electronic circuit and proper operation on harmonics. And it is known that each harmonic has an amplitude less then dominant in a few times in proportion to a harmonic number. Still the radiation power limits are restricted by international standards like FCC (USA) and EITS (Europe) and thus it is impossible to power similar RF IC card over large distance more than a few feet.
The mentioned above systems do not possess a battery of its own and which draw supply energy required for the functioning of the active electronic components of the responder circuit from the electromagnetic interrogation field, by means of which digital information stored in the responder may be detected. Furthermore, the mentioned above systems may provide the possibility of contactless modification of a data stored in the memory of a responder.
The non-contact IC cards used in such a systems are considered to be conventional according to dimensions and size, and, in general, a noncontact card has the shape of a portable member and a size generally equal to that of ordinary magnetic cards, and has internal coil antenna formed as a spiral copper foil pattern by etching or the like.
The operation of the RF noncontact IC card when a person who possesses the IC card passes, for example, through a special toll gate controlled by terminal, looks like electromagnetic wave serial exchange between the IC card and terminal over selected allowed channel of a communication link. However there are a very narrow windows in permitted radio-band on electromagnetic radiated fields, which are possible to use to power radio-frequency cards. Particularly at frequencies below 13.56 MHz, it is possible, by limiting the distance between the terminal (R/W) and the card (transponder) to derive the energy for the contactless smart card from the radio waves. Notwithstanding the frequency spectrum for a given radio systems is a limited communication resource (band width and consequently the data rate) and several users may be competing for this communication resource, that may guide to the collisions and interference, and of this kind systems can not provide reliable operation when more than one noncontact IC card is located in active area of a terminal.
One of the nearest to our invention embodiment is disclosed in U.S. Pat. No. 5,426,667 where the System for the contactless exchange of data between one or more transmitter/receiver devices and a plurality of responders is described. According to the invention, the responder is designed to exchange data via a microwave connection with a transmitter/receiver device operating in the microwave range, and to exchange data via an inductive coupling with an inductively operating transmitter/receiver device.
A system for the contactless exchange of data between at least one transmitter/receiver device and a plurality of responders, wherein at least one of the responders is designed to exchange data via a microwave connection with at least one of said at least one transmitter/receiver device operating in the microwave range and to exchange data via an inductive coupling with at least one inductively operating transmitter/ereceiver device, said at least one responder comprising a microwave antenna device, an inductively operating antenna device, and a data carrier, in which data is stored, wherein between the data carrier and the microwave antenna device means are connected for modulating a received microwave signal with data stored in the data carrier and wherein between the data carrier and the inductively operating antenna device means are connected for modulating an inductively received signal with data stored in the data carrier. However this embodiment operates at one constant frequency (low and/or high) and responders may operate entirely sharing the time to prevent collisions and interference. In addition this system is guarded against signal interception and deciphering on a software level solely and one may record easily the communication protocols and temper it. Moreover the frequency spectrum for a given radio system is a limited communication resource and several users may be competing for this communication resource, that may guide to the collisions and interference, and of this kind systems can not provide reliable operation when more than one noncontact IC card is located in active area of a terminal.
The goal of present invention is to merge the convenience of a conventional noncontact radio frequency cards with advanced performances of a complicated apparatuses, like present modern an in-vehicle units for automatic toll collection, comprising functions of a reading/writing from IC cards and transmitting payment information to a distant road collection station. Herein the operating distance is increased and the simultaneous stable non-collision and non-interference operation of a several cards is provided. Furthermore the hopping communication channels support the preventing of interception and easy decoding and deciphering of radio-frequency signal with an attempt of a tempering.
Another object of the present invention is to shorten the time of passing through the toll gates, because if prepaid balance is not enough to pay, the debt is recorded into the IC card memory and the next card entering into an ATM machine is accompanied with payment of all previous debts. Besides, the eliminating of reader/writer functions from in-vehicle unit prevents a possibility of hacking of in-vehicle unit with a purpose to avoid reader/writer and send a fraud information about money transfer.
Next purpose of a preferred embodiment is the utilization of the single versatile noncontact IC card which may, like present modern IC cards do, to store prepaid value, keep the balance and refund debt automatically while the next operation of money charging into card occurs. The same card may be used in many applications with and without the in-vehicle unit like in automatic vehicle identification, parking, in realtime highway toll collection systems, in public transportation for fare collection, and remote authentication.
Additional destination of a preferred embodiment is to provide a low cost solution of a system, comparable with that of the modern noncontact IC card which is built using the already created inexpensive production technology of internal spiral coil antenna for conventional economical and standard RF Cards. Using the same technology the printing of a conductive strip antenna do not add a significant price.
The other target of a preferred embodiment is to obtain a low cost of in-vehicle unit due to canceling it""s additional functions as participation in data transmission, reading/writing from/to the card and balance calculation, and elimination of all gadget displays.
Additional object of the present invention is to obtain the non-contact IC card of a conventional size and, in general, a noncontact card must have the shape of a portable member and a size generally equal to that of ordinary magnetic cards having internal coil antenna formed as a spiral copper foil pattern by etching or the like.
1. In view of the described above problems and goals, an object of a present invention is to provide a two-way radio-based electronic toll collection method to be implemented on highway comprising the steps of providing communication terminal (Reader/Writer) with RF antenna which transmits continuously downlink energy-transmitting signal of first predetermined frequency, and generates a communication hopping channels for bi-directional data transfer, moreover hopping frequency is synthesized of said first predetermined frequency used as reference. Next phase of said toll collection method is to furnish the each vehicle passing along the highway with a noncontact IC card capable to receive said downlink energy-transmitting signal of first predetermined frequency in order to power the electronic components integrated within IC card, which provide the synthesizing of a communication channels of hopping frequency, synchronized by the said first radio-frequency used as reference, and wherein a noncontact card scrolls, detects and selects the available communication hopping channels to establish bi-directional data transfer. In additional the method comprises the installing of in-vehicle unit in each vehicle passing along the highway to receive the said downlink energy-transmitting signal of first predetermined frequency and to verify the field strength of said energy-transmitting signal in order to enable regeneration by in-vehicle unit of an extra portion of energy-transmitting alternating field at the second predetermined frequency with a purpose to feed a noncontact IC card and provide a regular IC card operation. In this method the exchanging of a toll collection and payment information wirelessly between said communication terminal and said noncontact IC card via said bi-directional communication hopping channels start after the one of the channels of available plurality is selected. Said method permits multiple users to communicate over said bi-directional communication hopping channels preventing collisions, interference, interception and easy deciphering of toll collection and payment information.
Additional object of a present invention is to provide a noncontact IC card, a terminal for use with noncontact IC card and an in-vehicle carried unit which can radiate additional portion of electromagnetic energy over inductive coupling to power noncontact IC card and a noncontact IC card system having a roadside terminal for use with noncontact IC card and an in-vehicle carried unit and noncontact IC card, wherein the road terminal radiates first radio-frequency of an energy-transmitting signal to power said IC card, and wherein first radio-frequency is used by the IC card as a reference clock to synthesize higher band frequencies to provide a sequence of communication channels using channel hopping in order to realize bi-directional data communication, and wherein card antenna circuit provides parallel resonant to derive operating power from the energy-transmitting signal transmitted by the road terminal (stationary member), and wherein card antenna circuit provides series resonant to transmit and receive data, and wherein in-vehicle unit provides supplementary (extra) portion of electromagnetic radiation to power IC card when IC card located distantly from terminal.
Herein in preferred embodiment the parallel resonant circuit antenna presents a high impedance resulting in a large voltage with a small current flow, meanwhile the series resonant circuit antenna presents a low impedance which results in a large current with a small applied voltage. The series resonance minimize the effect of the high frequency transmitted/received signal on the low frequency power signal, enabling simultaneous energy receive and data transmit/receive operation through the same physical antenna circuit.